YAMADA Global Series User manual

MAINTENANCE MANUAL
G25
Doc. No. NDP 540M-03

WARNING
• For your own safety, be sure to read these procedures carefully before performing
maintenance on this product. After reading this document, be sure to keep it handy for future
reference.
This maintenance manual covers what you should know about maintenance of the Yamada G25A□
Diaphragm Pumps.
This edition is based on the standards for the April 2021 production run. Remember, the specifications
are always subject to change; therefore, some of the information in this edition may not apply to new
specifications.
·Warnings and Cautions
For safe use of this product, be sure to note the following: In this document, warnings and cautions are
indicated by symbols. These symbols are for those who will operate this product and for those who will be
nearby, for safe operation and for prevention of personal injury and property damage. The following
warning and caution symbols have the meanings described below. Be sure to remember their meanings.
If you ignore the warning described and operate the product in an
improper manner, there is danger of serious bodily injury or
death.
If you ignore the caution described and operate the product in an
improper manner, there is danger of personal injury or property
damage.
Furthermore, to indicate the type of danger and damage, the following symbols are also used along with
those mentioned above:
This symbol indicates a DON'T, and will be accompanied by an explanation on something
you must not do.
This symbol indicates a DO, and will be accompanied by instructions on something you
must do in a certain situation.
WARNING
• Before starting maintenance work, cut off the feed air and clean the pump. If air pressure or
residue remain in the pump, there is danger of explosion, or possible poisoning resulting in
serious injury or death if chemicals adhere to the skin or are accidentally swallowed.
(For details on cleaning the pump, refer to Chapter 6 of the Operation Manual.)
• When replacing parts, be sure to use the recommended genuine parts or Equivalents. Use of
other parts may cause a malfunction of the product.
(Refer to Parts List the separate sheets.)
CAUTION
• When it is instructed that special tools must be used, be sure to use the specified tools.
Otherwise, the pump may be damaged.
• Refer to “10.1 Specifications” in the Operation Manual. Also, remember that the pump is
heavy, and extreme care must be taken when lifting it.
WARNING:
CAUTION :

Table of Contents
·Warnings and Cautions
·Table of Contents
1.Principles of operation------------------------------------------------------------1
2. Maintenance and Tools
2.1 Maintenance -----------------------------------------------------------------------1
2.2 General tools-----------------------------------------------------------------------1
2.3 Special tools------------------------------------------------------------------------1
2.4 Misc. ---------------------------------------------------------------------------------1
3.Ordering Replacement parts ---------------------------------------------------1
4.Balls, Valve seats
4.1 Removal -----------------------------------------------------------------------------2
4.2 Inspection --------------------------------------------------------------------------3
4.3 Installation-------------------------------------------------------------------------3
5.Diaphragm and Center rod
5.1 Removal -----------------------------------------------------------------------------4
5.2 Inspection --------------------------------------------------------------------------4
5.3 Installation-------------------------------------------------------------------------5
6.Guide bush
6.1 Removal -----------------------------------------------------------------------------6
6.2 Inspection --------------------------------------------------------------------------6
6.3 Installation-------------------------------------------------------------------------6
7.Spool valve assembly and Sleeve
7.1 Removal -----------------------------------------------------------------------------7
7.2 Inspection --------------------------------------------------------------------------8
7.3 Installation-------------------------------------------------------------------------8
8.Retightening of Tie rods----------------------------------------------------------8

1
1. Principles of operation
There are two diaphragms fixed to the center rod, one at each end. When compressed air is supplied to air
chamber b (right side, see Fig.1.1), the center rod moves to the right, the material in material chamber B is
pushed out, and at the same time material is sucked into material chamber A.
When the center rod is moved full-stroke to the right, the air switch valve is switched, compressed air is
sent to air chamber a (left side, see Fig.1.2), and the center rod moves to the left. The material in material
chamber A is pushed out, and at the same time material is sucked into material chamber B.
Through repetition of this operation, material is repeatedly taken in and discharged out.
2. Maintenance and Tools
2.1 Maintenance
Pump maintenance is recommended after each of the following periods.
Estimated inspection timing (Based on water at room temperature)
Type of diaphragm Operation hours (h)
NBR 500
PTFE 150
TPEE 750
TPO 750
* In critical operations where preventive measures need to be taken, it is recommended to inspect
diaphragms after every three months of operation.
2.2 General tools
▪Socket wrenches 10mm, 17mm
▪Open-end wrenches 10mm, 17mm, 22mm
▪Hexagonal box wrenches 5mm
2.3 Special tools (sold separately)
▪Capremover ▪Sleeve remover
Purpose:Removingthecap Purpose: For removing sleeves
2.4 Misc.
▪Assembly oil Turbine oil none addition class 1(equivalent to ISO VG32 grade)
▪Nuts
M14 X 1.5 class 3
▪Grease Urea grease grade (NLGI) No.2
3. Ordering Replacement parts
For accurate and speedy shipment of parts, be sure to order the right parts for your model to distributor
Indicate the part numbers, descriptions, and quantities.
Fig.2.2
(Part No. 713148)
Fig.1.1 Fig.1.2
Fig.2.1
(Part No. 717114)

2
4. Balls, Valve seats
4.1 Removal
▪Remove 4 mounting bolts from upper manifold and remove
the manifold. [Fig.4.1]
▪Remove the O ring, ball, valve seat. [Fig.4.2]
▪Turn over the main body assembly. [Fig.4.3]
▪Remove 4 mounting bolts from lower manifold and remove
the base and the manifold. [Fig.4.3]
▪Remove the O ring, valve seat, ball. [Fig.4.4]
Fig.4.1
Fig.4.2
Fig.4.3
Fig.4.4

3
4.2 Inspection
▪Ball [Fig.4.5]
Measure the outside diameter, and if it is outside the usable
range, replace the ball.
Usable range of Ball
SØ 24.3 - SØ 27.8 mm
▪Valve seat [Fig.4.6]
Measure the dimension shown at left, and if it is outside the
usable range, replace the seat.
Usable range of Valve seat
4 mm or less
▪O ring (other than PTFE)
If O ring is worn out or cracked, replace it.
4.3 Installation
For installation, see [Exploded View] on the separate sheet and install in the reverse order of disassembly.
Tightening torque for manifold retainer bolts or nuts
AN, AH, AS 10 N･m
AT 20 N･m
< NOTE >
▪Make sure there is no dust on the seal surface and the seal
is not damaged.
▪Replace the PTFE O ring regardless of its condition.
Fig.4.5
Fig.4.6

4
5. Diaphragm and Center rod
5.1 Removal
▪Remove the O ring, ball, valve seat (see “ 4.1 Removal”).
▪Remove the 12 retainer bolts from the out chamber, and
remove the out chamber. [Fig.5.1]
▪After the center disk on one side have been removed using
the spanner 22 mm etc., remove the center disk and
diaphragm. [Fig.5.2]
▪Remove the center disk and center rod from the opposite side
of the main body.
▪Remove the center disk on the opposite side using the double
nuts. [Fig.5.3]
▪Remove the center disk and diaphragm.
5.2 Inspection
▪Diaphragm
If the diaphragm is worn out or damaged, replace it.
Never replace just one diaphragm.
▪Center rod [Fig.5.4]
Measure the diameter, and if it is outside the usable range,
replace the rod.
Usable range of center rod
φ17.95 -φ18.00 mm
Fig.5.1
Fig.5.2
Fig.5.3
Fig.5.4

5
5.3 Installation
For installation, see [Exploded View] on the separate sheet and install in the reverse order of disassembly.
▪Apply grease to the center rod, and insert it into the main
body.
▪Keep the convex side to the outside for diaphragm.
▪For the model with NBR diaphragm, put the spacer into
outside of the diaphragms. (cf. Fig.5.5).
▪For the model with PTFE diaphragm, put the Orings into
both side of the diaphragms. (cf. Fig.5.6).
▪Pull out the diaphragm to one side and assemble the out
chamber with Fig. 5.5、5.6、5.7 condition. Bolts should not be
fully tightened at this point.
▪Pull out the diaphragms to the other side and assemble the
out chamber with Fig. 5.5、5.6、5.7 condition. Bolts should not
be fully tightened at this point.
▪Place the pump on flat surface, stand the pump upright and
tighten all the bolts fully.
< NOTE >
▪Make sure there is no dust on the seal surface in order to
prevent seal damaged.
▪Replace the PTFE O ring by new one.
▪Tighten the bolts that balance should be equal from both
side on diagonal line with even torque.
Tightening torque for center rod and out chamber
Center rod Out chamber
NBR 40 N･m 10 N･m
PTFE, TPO, TPEE 20 N･m
Fig.5.5
Fig.5.6
Fig.5.7
■AN type
■AT type
■AH, AS type

6
6. Guide Bush
6.1 Removal
▪Remove the diaphragm and center rod etc. (see “5.1
Removal”).
▪Remove 8 mounting bolts from the air chamber and remove
the air chamber and the gasket. [Fig.6.1]
▪Draw out the guide bush A, B, C. [Fig.6.1]
6.2 Inspection
▪Guide bush [Fig.6.2]
Measure the inside diameter, and if it is outside the usable
range, replace the guide bush.
Usable range of guide bush
Guide bush A, C φ18.4 -φ18.7 mm
Guide bush B φ18.3 -φ18.6 mm
▪O ring
If the O ring is worn out or cracked, replace it.
6.3 Installation
For installation, see [Exploded View] on the separate sheet and install in the reverse order of disassembly.
Tightening torque for air chamber retainer bolts
18 N•m
<NOTE>
▪Make sure there is no dust on the seal surface and the seal
is not damaged.
▪Apply grease to O ring.
▪Fill the inside diameter groove of the guide bush B with
grease.
Fig.6.1
＜Guide bush
A
＞
＜Guide bush B＞
＜Guide bush C＞Fig.6.2

7
7. Spool valve assembly and Sleeve
7.1 Removal
▪Remove 4 bolts fixing the valve body assembly and draw out
the valve body assembly from the main body. [Fig.7.1]
▪Remove the cap A using the cap remover.
(special tool: Part No. 717114). [Fig.7.2]
▪Remove the cushion, and then push out the Spool valve
assembly from opposite side. [Fig.7.3]
▪Remove the sleeve using the sleeve remover (special tool:
Part number 713148). [Fig.7.4]
Fig.7.1
Fig.7.2
Fig.7.3
Fig.7.4

8
7.2 Inspection
▪Spool valve assembly
Seal ring [Fig.7.5]
Measure the outside diameter of the seal ring, and if it is
outside the usable range, replace the Spool valve assembly.
If the seal ring is worn out or cracked, replace Spool valve
assembly.
Usable range of Seal ring
Part to measure A φ12.58 mm and over
Part to measure B φ17.88 mm and over
▪Sleeve [Fig.7.6]
Measure the inside diameter, and if it is outside the usable
range, replace the Sleeve.
Usable range of Sleeve
Part to measure A φ12.66 -φ12.79 mm
Part to measure B φ17.96 -φ18.09 mm
▪O ring, Packing
If the O ring is worn out or cracked, replace it.
<NOTE>
▪Spool valve assembly and Sleeve must be replaced complete
set. Unable to replace individual component.
7.3 Installation
For installation, see [Exploded View] on the separate sheet and install in the reverse order of disassembly.
Tightening torque for Valve body assembly attaching
5 N･m
<NOTE>
▪Make sure there is no dust on the seal surface and it is not
damaged.
▪Fill the packing mounting part of the spool with grease and
reinstall the packing.
8. Retightening of Tie rods
▪The torque should be applied on the occasion of
(1) Right before the pump to use.
(2) There are any leaks of material on daily inspecting a
pump.
<NOTE>
▪Tighten the bolts that balance should be equal from both
side on diagonal line with even torque.
▪Retighten the Out chamber and then the manifold in this
order. [Fig.8.1]
Retainer bolts from the
out chamber
Retainer bolts from the
manifold
AN 10 N･m
AT 20 N･m
AH, AS 20 N･m 10 N･m
Fig.8.1
Fig.7.5
Fig.7.6

YAMADA
EUROPE B.V.
Aquamarijnstraat 50,7554 NS Hengelo (O),The Netherlands
PHONE : [phone]
FAX : [phone]
E-mail : [e-mail]
Web : www.yamada-europe.com
Manufactured by
YAMADA CORPORATION
INTERNATIONAL DEPARTMENT
1-1-3, Minami-Magome,Ota ku, Tokyo, 143-8504, Japan
PHONE : [phone]
FAX : [phone]
E-mail : [e-mail]
Web : www.yamadacorp.co.jp
202104.2549 NDP540
M